Trip Indicator

The Task Manager reviews Powertrain Control Module (PCM) inputs during each key cycle to determine if the conditions required for each individual test have been met before it allows that test to be performed. Requirements vary with each test, but typically include information such as elapsed time since start-up, engine coolant temperature, RPM, MAP, and throttle position.





"Trip" is a difficult concept to define because the requirements for a trip vary depending on the test being run (see figure above). These conditions can include seemingly unrelated items such as driving style, length of trip, and ambient temperature. The minimum requirement for a trip is that it includes one key cycle and usually some drive time before a test is performed. Vehicle tests vary in length, and may be performed only once per trip, or may be performed continuously. If the pertinent enabling conditions are not met for the O2 sensor, catalyst, and EGR monitors during that key cycle, the tests may not run at all.

NOTE: California and some other states require the PCM to indicate that all monitors have passed before issuing license plates. Removing the vehicle's battery to erase DTCs before testing erases any record of passing a monitor. If the monitor does not complete a trip on subsequent key cycles, the vehicle can fail a licensing test.